If it is a very busy time of year or day and there are queues of people on the boat docks, be prepared for the boats to only allow a specific number of Guests from each Resort per pick up.
We generally walk, but one night we wanted to take the boat to MGM from Yacht Club with our grandmother. Because it was about 90 mins from park closing and apparently loads of Guests wanted to see Fantasmic, lines were lengthy on the docks. As a result, 10 Guests were allowed on at Yacht/Beach and then ten from BoardWalk, then Swan/Dolphin got to fill in the rest of the seats.
Walk to Epcot and MGM, it is usually quicker if you are capable. Just a heads up that the boat transportation can sometimes be less than adequate.